Trial of Oligometastasis SBRT With Immediate, Simulation-Free Treatment Delivery (OLIGO-SWIFT)

Inclusion Criteria: * Participants must have histologically, cytologically, or radiographically or confirmed cancer that is oligometastastatic (defined in this protocol as up to 5 active sites of disease at time of trial enrollment). Note that previous ablative therapy to the treatment site (excluding prior external beam radiation) is permitted, such as previous microwave ablation or radiofrequency ablation. * Age ≥18 years. * Performance status: Eastern Cooperative Oncology Group (ECOG) Performance status ≤ 2 * Estimated life expectancy of at least 3 months * Participants must be considered a candidate for SBRT by the treating physician * Prior chemotherapy or biological treatment is allowed, but any active oncological treatment should be stopped at least 1 week prior to radiation therapy and renewed no sooner than 1 week following radiation therapy, with the exception of endocrine therapies, which can continue through radiation treatment. * Participants must have the ability to understand and the willingness to sign a written informed consent document. * Participants must have a diagnostic CT, MRI, or PET/CT of the site(s) intended for treatment, with or without contrast, acquired no more than 30 days prior to study consent. Exclusion Criteria: * Prior radiotherapy to any site overlapping with the projected site for protocol treatment. * Participants with isolated vertebral metastases except for sacral spine; participants with osseous spine disease can be treated upon this protocol, but those sites (cervical, thoracic, lumbar spine) are not permitted for treatment upon this study. Such participants could be enrolled for treatment to other, concurrent (e.g., visceral, or non-spine bone) disease on this study. * Pregnant or breastfeeding women are excluded from this study. * Women of childbearing potential must have a negative pregnancy test within 14 days of study entry. If pregnancy test is not clinically indicated as determined by the treating physician or protocol principal investigator (PI), documentation of this exception is sufficient in lieu of a pregnancy test.